semi合集-English.pdf - 第770页

SEMI E104-0303 © SEMI 2000, 2003 6 8.3 Humidity 8.3.1 The LPPD sh ould wor k correctly at an ambient humidity range RH as specified in ISO 14644-5. If the use of an LPPD at an exte nded ambient hum idity range is require…

SEMI E104-0303 © SEMI 2000, 2003 5

5.2 Space, Distances, and Installation

5.2.1 The use of an LPPD should not have a negative

impact on the process performance. The sensor location

in the equipment shall ensure an optimum use of the

sensor sensitivity in order to allow a measurement

which is representative of the main particle flow. The

influence of the process and the process equipment on

the LPPD shall be minimized (thermal background

radiation, vibrations etc.)

5.2.2 The standard does not specify where an LPPD

should be located in original equipment, or where space

should be allowed for retro-fitting. It is recognized that

the location is dependent on factors including transport

behavior of particles, thermal background radiation etc.

The designers of semiconductor process equipment

should resort to the experience of application engineers

of the LPPD suppliers and the end users. However, in

either case designers shall take into account access

requirements for maintenance and re-calibration. In the

case of retro-fitting, the design should facilitate sensor

installation rather than hinder it.

6 Electrical Interfaces

6.1 Sensor/Controller Communication

6.1.1 Depending on the choice of the LPPD supplier

and the semiconductor equipment manufacturer, one of

the following interfaces for data exchange between the

LPPD and process equipment controller should be used.

6.1.2 Sensor/Actuator Network (SAN)

6.1.2.1 The electrical interfaces of the Sensor/ Actuator

Network are described in the suite of SEMI E54

standards.

6.1.3 Serial Communication

6.1.3.1 RS 232 C (V.24/V.28)

6.1.3.2 RS 485

6.1.4 Others

6.1.4.1 IEEE 488 or IEC 60625

6.2 Others

6.2.1 Sensor calibration output (direct analog output)

6.2.1.1 The analog output for access to the sensor

signal used for calibration purpose should be supported.

7 Communication Interfaces

7.1 Sensor Bus Communication

7.1.1 It is recommended to use a Sensor/Actuator

Network (SAN) for the intra-tool communication

between the LPPD controller and the controller of the

process equipment. This communication is based on a

suite of SEMI standards including a network

communication standard, several common device

models (DeviceNet, SDS, Lonworks, ProfiBus etc.),

and the specific device model for the sensor. The

Network is described by the following suite of SEMI

standards: SEMI E54. The specific device model for

ISPM is described by SEMI E54.10.

7.2 SEMI Equipment Communication (SECS)

7.2.1 If LPPD controllers provide the collected particle

data to the process equipment controller, factory

automation system, or SPC system, the SECS tool-to-

host communication could be used. SECS is described

in the following standards:

• SEMI E5

• SEMI E4

• SEMI E37

7.3 Attribute Definitions

7.3.1 SEMI E54.10 addresses the minimum attributes,

services and behavior an ISPM-device shall support. If

any attributes and services are used by communication

of the ISPM and the equipment controller via IEEE 488

(IEC 60625) or serial communication, they should be

concurring.

8 Operating Conditions

8.1 To specify the operating conditions of an LPPD

(temperature, humidity, electromagnetic compatibility,

vibrations etc.) refer to the following standards:

• IEC 60654-1

• IEC 60654-2

• IEC 60654-3

• IEC 60654-4

• IEC 60801-1

8.2 Temperature

8.2.1 The LPPD should work correctly at an ambient

temperature range T

as specified in ISO 14644-5. If

the use of an LPPD at an extended ambient temperature

range is required, the specific LPPD should comply

with these conditions.

8.2.2 The temperature T

inside the pump line or

inside the process equipment depends on the actual

application. The application engineers shall check the

use of LPPDs under these specific conditions. The

temperature T

is measured at the flange which the

LPPD is mounted on.

SEMI E104-0303 © SEMI 2000, 2003 6

8.3 Humidity

8.3.1 The LPPD should work correctly at an ambient

humidity range RH as specified in ISO 14644-5. If the

use of an LPPD at an extended ambient humidity range

is required, the specific LPPD should comply with

these conditions.

8.4 Electromagnetic Compatibility

8.4.1 The equipment should comply with SEMI E33.

8.4.2 Sensors will be incorporated into equipment

either as original equipment or retro-fitted. In either

case, the sensors or the equipment of which they are a

part should comply with the current regulations

covering EMC in the country or region where the

equipment or sensor is used.

8.5 Vibrations

8.5.1 Process equipment designers are advised to

consider the impact of vibration on the performance of

the sensor while it is collecting data. Therefore, they

should minimize vibrations. The designers of the LPPD

sensors are also advised to consider the impact of

vibrations on the equipment at a time the sensor is not

collecting any data. It might be possible that these

vibrations are stronger than those occurring while the

sensor is collecting data.

9 Reference Calibration Procedure

9.1 The response of real contamination particles,

typically with refractive indices and shapes different

from calibration particles, will differ slightly from the

results obtained by the procedures in this document. It

is known that LPPDs with different optical design may

not produce the same data from identical aerosol

samples. This may happen even with similar LPPDs if

calibration differences have occurred. Therefore, before

the first use the sensor should be calibrated by the

manufacturer. This calibration should be compliant

with or should be reviewed with the following reference

calibration equipment and procedure. This reference

calibration allows the characterization of the

performance of the LPPD under test. The LPPD should

be recalibrated at regular intervals and also in case of

unusual measurement readings to ensure correct results.

9.1.1 The parameters calibrated for LPPDs with sizing

capability are:

• Sizing calibration,

• Resolution,

• Zero counting,

• Counting efficiency, and

• Sensitivity.

9.1.2 The parameters calibrated for LPPDs with non-

sizing capability are:

• Zero counting, and

• Counting efficiency.

9.1.3 Field calibration may not necessarily require the

calibration of all parameters performed by calibration at

the sensor manufacturers site.

9.1.4 Due to the fact that different LPPDs might be

working with different detection areas A

, the number

of counts should be printed out in counts per mm

detection area. Therefore, a comparison of the

measurement results of different LPPDs is possible.

The size of the detection area A

shall be reported in

the calibration report form. Any changes of calibration

parameters or of the calibration setup shall be reported

in the calibration report form. A copy of the calibration

report form shall be delivered with the sensor.

9.2 Apparatus

9.2.1 Materials

9.2.1.1 Particles

9.2.1.1.1 Calibration particles are polymer spheres

composed of polystyrene or a similar polymer, having a

refractive index of 1.58-1.61+ 0i (absorption coefficient

α = 0), a sizing accuracy of at least 95%, and a size

distribution in which the coefficient of variation is 5%

or less. They should be traceable to a nationally or

internationally recognized standard (e.g. NIST

9.2.1.1.2 The calibration particles are normally

supplied in concentrations too high to be used directly

in aerosol generators. The particles should be dispersed

and diluted in either deionized, distilled water in

accordance with ASTM D1193, Type 1, or Isopropanol.

The diluent should be cleaned using a filter with a pore

size no more than 10% of the size of the particles being

used. The solution should be stored in a clean container.

For generation and dilution of the suspension see

Appendix 3. After generation the particles should be

neutralized to avoid surface charge. For all tests

described in this document, the concentration should be

no more than 25% of the maximum recommended

concentration limit specified by the manufacturer. For

calibration a suitable set of particle sizes shall be used.

This set should contain at least 5 sizes that cover the

LDL size to at least 80% of the specified maximum size

measurement capability of the LPPD.

NOTE 4: Most of the ISPM sensors are based on light

scattering. The intensity of the scattered light detected by a

photodetector depends on intensity, polarization state, and

9 National Institute of Standards and Technology, 100 Bureau Drive,

Gaithersburg, MD 20899-0001, USA

SEMI E104-0303 © SEMI 2000, 2003 7

wavelength of the incident light beam, diameter, shape, and

refractive index of the particle and the suspension fluid, as

well as on the geometrical layout of the collection optics and

detector. In the particle size range near the wavelength (0.1λ

< d

< 10λ), large oscillations can be seen in the intensity

curve of the light scattered by spherical particles as a function

of all these parameters. This phenomenon should be taken

into account when selecting a suitable set of particle sizes for

calibration. The used calibration particles should be within a

monotonic response range of the LPPD response curve.

9.2.1.2 Zero Gas

9.2.1.2.1 Clean air or nitrogen filtered with a ULPA

filter.

NOTE 5: The calibration will be executed under atmospheric

pressure and zero gas. In semiconductor manufacturing,

pressure and process gases will differ from the calibration

conditions. This will affect the refractive index ratio of the

particles and the process gas and consequently the scattering

from the particles.

9.2.1.3 Surfaces

9.2.1.3.1 The materials of pump lines and other

components should be conductive to minimize

electrostatic interaction with the particles.

9.2.2 Instrumentation (see Figure 1) — Some LPPDs

may require specialized equipment not generally

available. Please contact the LPPD manufacturer.

9.2.2.1 Fan System

9.2.2.1.1 The fan or pump system should be adjustable

to transport the aerosol and the zero gas within the

stipulated velocity range v

L, min

... v

L,max

, specified by

the manufacturer of the LPPD.

9.2.2.2 Filter System

9.2.2.2.1 The ULPA filter system is used for gener-

ation of zero gas. The filter system should be capable of

removing particles at the minimum size detectable by

the LPPD or the reference particle counter.

9.2.2.3 Aerosol Generator

9.2.2.3.1 An atomizer converts the monodisperse

particle suspension to an aerosol by using compressed

zero gas for generation and transportation of the

particles. The aerosol generator should generate

monodisperse particles as defined in Section 9.2.1.1 in

constant and reproducible concentration C

under

constant and reproducible volume flow rate V´

. The

variation in particle concentration shall be no more than

10% as measured by the reference particle counter over

a time period of 10 times or more of the sample

measurement time. The generation should comply with

the German VDI-Richtlinie 3491, or an equivalent

standard in other countries.

9.2.2.4 Aerosol dryer

9.2.2.4.1 The monodisperse polymer spheres in the test

aerosol shall be thoroughly dry to avoid that the

particles have a water layer which would increase their

size. A diffusion dryer, another appropriate instrument,

or adequately dry dilution air should be used to dry the

particles. The diffusion dryer uses silica gel desiccant to

remove the moisture. The desiccant shall either be new

or freshly regenerated. The design flow rate of the

aerosol dryer shall at least match the output flow rate of

the aerosol generator.

NOTE 6: Some diffusion dryers may precipitate polymer

spheres and add other particles when the aerosol gets in direct

contact with the silica gel.

9.2.2.5 Neutralizer

9.2.2.5.1 An aerosol neutralizer should be connected in

line with the dryer to reduce electrostatic charges on the

dry polymer spheres and to avoid electrostatic

interaction with each other or the line wall. The design

flow rate of the aerosol neutralizer shall at least match

the output flow rate of the aerosol generator.

NOTE 7: Some electrostatic neutralizers may produce a large

number of ultra-fine particles which will combine with the

calibration aerosol.

9.2.2.6 Aerosol Size Separator

9.2.2.6.1 In the case of calibration with ultra-fine

particles, a system should be used to separate single

polymer spheres from the residual particles resulting

from vaporization of solutions and aggregate particles

consisting of several spheres. The size separation could

be achieved with an electrostatic classifier or a

diffusion battery.

9.2.2.7 Aerosol Dilution

9.2.2.7.1 If the particle concentration behind the

aerosol generator is too high, the particle flow shall be

diluted to achieve the required concentration and to

avoid coincidence errors. The dilution should comply

with the German VDI-Richtlinie 3491, or an equivalent

standard in other countries.

9.2.2.8 Aerosol Line System

9.2.2.8.1 The system consisting of

• the aerosol generator,

• the aerosol dryer,

• the neutralizer,

• the particle size separator,

• the dilution stage, and

• tubing connecting the devices with each other and

the filtered, dried and compressed zero gas.